Paper Title
DETECTION OF CLIMATE CHANGE TRENDS OVER THE MARIANA REGION

Abstract
The Mariana Region has always been at the frontlines of the great challenge of climate change. Sea level rise threatens the very survival of small islands over the region, especially because it has a significant impact on freshwater resources. Due to the relatively small size of catchments receiving rainfalls, the small islands rely only on precipitation for drinking water and irrigation water resources. Therefore, changes in precipitation patterns such as intensity, occurrences, and extreme events result directly in water availability on the islands. The natural variability and complexity of climate systems make it difficult to detect climate change. In this study, I used 18 climate change detection indices, including 14 core indices facilitated by ETCCDI and four use-defined indices. The indices are calculated for different timeframes (annual, two-seasonal and four-seasonal) using daily precipitation data and maximum and minimum temperatures from a network of 14 gauged stations in Guam for the period 1953- 2021. Mann-Kendall’s tau-based slope estimator is implemented for the calculated indices. Temperature trend analysis results indicate that Guam’s climate is getting warmer year by year. The values of its seasonal maximum of Tmax (TXx) are 0.036℃/year for the dry season and 0.025℃/year for the wet season. Regarding rainfall trends, I conducted the trend analyses by examining two different features -- basic statistics and extreme statistics. Statistically significant trends in total rainfall amount were detected during the wet season (JAS and OND). In particular, strong trends in rainfall occurrences are observed at 64% of the total rain gauges during the JAS period. In addition to the basic statistics, trends analysis results for extreme rainfall events reveal that some stations on Guam receive more amounts of rainfalls and more days exceeding 10 mm/day or 20 mm/year during the wet season. Strong increasing or decreasing trends in both basic statistics and extreme statistics of rainfall were observed during the wet season. It implies that the climate system over Guam is becoming more extreme. Keywords - climate change detection, temperatures trends, rainfall trends, pacific islands